OS 10.5 - Anti Virus Required?

Just been reading Mac Format, a UK magazine dedicated to the Mac. They are running a feature on Anti Virus programs for the Mac. They are recommending iAntiVirus available: http://www.iantivirus.com/ for free.

I was just wondering what you guys thought, do you use Anti Virus software?

I must admit I don't really want to install Anti Virus thats one of the reasons why I love the Mac but I also don't want to take risks.

i think is still no virus on mac, but when i try to surf using safari thats were the problem starts even i went to yahoo.com it redirect to other website its just like a search engine also but it has poker porn. i dont know what that is i have to restart my system to get that out.